This invention relates generally to absorbent articles for absorbing body fluids and exudates. More particularly, the present invention relates to a method for forming an absorbent structure having improved leak prevention and/or fluid flow control.
A wide variety of types of structures are known in the art for use in or as absorbent articles, particularly disposable absorbent articles, used to collect various body fluids and exudates. Commercial absorbent articles include diapers, adult incontinence products, sanitary napkins and bandages. Disposable products of these types generally comprise components for receiving, absorbing and retaining fluids. Typically, the components of such articles include a liquid permeable topsheet, an absorbent core and a liquid impermeable backsheet.
The components of typical absorbent articles are commonly plied or arranged in a horizontal fashion with a major planar surface facing the fluid intake area, e.g., the body of the wearer. In such absorbent articles, the nature or make-up of the fluid communicating therethrough can and typically will change as such fluid traverses though the horizontal ply or plies. Thus, such absorbent articles may experience undesirable horizontal dependency between components. Further, the fibers which customarily make-up the absorbent core are often orientated randomly with fibers within a mat in a lateral neighboring arrangement such that the fluid intake typically wicks in a radial fashion or pattern.
One of the main objectives in the development of absorbent articles is to increase, improve or maximize utilization of the absorbent capacity of the article. In general, products of the type described above typically distribute fluids deposited on the topsheet in a circular pattern. Since such structures generally have a length that exceeds their width, such liquid distribution may undesirably result in the fluids, e.g., exudates, reaching the longitudinal side edges of the absorbent article prior to the desirable utilization of the absorbent capacity at the end regions of the absorbent article. As will be appreciated, such occurrence may undesirably increase the possibility or likelihood of leakage from the sides of the article despite the availability of unutilized or underutilized absorbent capacity in the end regions of the absorbent article.
Moreover, such absorbent articles can and may be subjected to a wide range of conditions and applications such as due to factors inherent or related to the environment in which the article is utilized. Thus, the fluids which may need to be absorbed thereby may vary in properties or parameters such as including flow rate as well as form, phase or composition. For example, exudates may be multiphasic and heterogeneous, such as in the case of menses which may include red blood cells, mucin, plasma and tissue debris, for example.
Sanitary napkins (also referred to as catamenial pads), feminine pads, overnight pads, panty liners and panty shields are designed to be worn by a female to absorb menses and other body fluids discharged before, during and after a menstrual period. Sanitary napkins are external devices which are designed to be aligned approximate the pudendum region of a human body and are generally held in position by being adhesively or mechanically attached to an undergarment. Sanitary napkins also typically differ from panty liners and panty shields in several notable ways. Sanitary napkins are generally larger in size and have a more defined 3-dimensional configuration, are thicker in caliper and have a greater fluid capacity than panty liners or panty shields.
In view of the desire to provide increased comfort to the wearer and to minimize the appearance of the presence of such absorbent articles there is an ongoing demand and need for smaller or less bulky absorbent articles. Thus, there is a need and a demand for improved absorbent pad assemblies and absorbent articles such as may result in more complete utilization of the absorbent capacity thereof and such as may more effectively and efficiently respond to the possibly wide range of operating and performance conditions to which such assemblies and articles can be exposed.
In addition, there is a need and a demand absorbent structures which, in association with the absorbency of particular body fluids, more readily permit or provide the simultaneous or near simultaneous exposure of such fluids to absorbent materials of different selected absorbency. Further, there is a need and a demand for an improved technique or method of forming such absorbent structures. In particular, there is a need and a demand for such a formation technique or method which is either or both simpler or more effective than otherwise known or available.
A general object of the invention is to provide an improved method of forming an absorbent pad assembly, absorbent article or other selected absorbent structure or product.
A more specific objective of the invention is to overcome one or more of the problems described above.
The general object of the invention can be attained, at least in part and in accordance with one embodiment of the invention via a specific method for forming an absorbent article having an absorbent pad assembly with an outer fluid-contacting surface including discrete portions of different absorbency. A method, in accordance with one specific embodiment of the invention, involves helically winding at least first and second absorbent pad materials adjacently about a shaft member whereby at least a portion of each of the first and second absorbent pad materials includes an outer surface exposed portion.
The prior art generally fails to provide absorbent pad assemblies and absorbent articles which make as complete or full, as may be desired, utilization of the absorbent capacity of the respective absorbent structure. The prior art also generally fails to provide absorbent pad assemblies and absorbent articles which can respond either or both as effectively and as efficiently as may be desired to the possibly wide range of operating and performance conditions to which such assemblies and articles can be exposed. In particular, the prior art generally fails to provide such absorbent pad assemblies and absorbent articles of as simple as desired construction, fabrication and/or formation.
The invention further comprehends a method for forming an absorbent article having an absorbent pad assembly with a longitudinal axis and an outer fluid-contacting surface including discrete portions of different absorbency. In accordance with one embodiment of the invention, such a method includes helically winding at least first, second and third absorbent pad materials adjacently about a shaft member whereby at least a portion of each of the first, second and third absorbent pad materials includes an outer surface exposed portion. The absorbent pad assembly is then flattened along the longitudinal axis thereof. An absorbent core including the flattened absorbent pad assembly is then placed between a backsheet and a topsheet so as to form the absorbent article.
In accordance with another aspect of the invention, the invention comprehends a specific absorbent pad assembly. An absorbent pad assembly, in accordance with one preferred embodiment, has a longitudinal axis and includes a first absorbent pad material having a first preselected absorbency and a second absorbent pad material having a second preselected absorbency, where the first and preselected absorbencies are different. At least one section of the first absorbent pad material and at least one section of the second absorbent pad material are adjacently disposed relative to each other and the at least one section of the first absorbent pad material and the at least one section of the second absorbent pad material each have an edge surface angularly orientated relative to the longitudinal axis.
The invention further comprehends a specific absorbent article. An absorbent article, in accordance with one preferred embodiment of the invention, has a longitudinal axis and includes an absorbent pad assembly which forms an outer fluid-contacting surface. The absorbent pad assembly includes first, second and third absorbent pad materials each having a respective preselected absorbency with the preselected absorbency of the second absorbent pad material being different than the preselected absorbency of the first absorbent pad material and the preselected absorbency of the third absorbent pad material being different than the preselected absorbency of the second absorbent pad material. At least one section of the first absorbent pad material and at least one section of the second absorbent pad material are adjacently disposed relative to each other and the at least one section of the first absorbent pad material and the at least one section of the second absorbent pad material each have an edge surface angularly orientated relative to the longitudinal axis. Also, the at least one section of the second absorbent pad material and at least one section of the third absorbent pad material are adjacently disposed relative to each other and angularly orientated relative to the longitudinal axis.
As used herein, references to xe2x80x9cabsorbent article(s)xe2x80x9d are to be understood to refer to products such as diapers, sanitary napkins, training pants, incontinent garments, overnight pads, panty liners, under arm shields and the like, which are used to absorb body fluids and exudates, such as urine, menses, blood, perspiration and other excrements discharged by the body.
Other objects and advantages will be apparent to those skilled in the art from the following detailed description taken in conjunction with the appended claims and drawings.